State‐contingent analysis of farmers’ response to weather variability: irrigated dairy farming in the Murray Valley,Australia

The agricultural sector is commonly regarded as one of the most vulnerable to climate change. Current understanding of the impact of climate change on this sector relies on the underlying assumptions about farmers’ possible responses to weather variability, including changes in crop choice, input combinations and land management practices. Many previous analyses rely on the implicit (and restrictive) assumption that farmers operate under a fixed technology set across different states of nature. This assumption, represented through stochastic production or profit functions, is commonly made but seldom tested and may understate farmers’ responses to climate change if state‐contingent production technologies are, in reality, more flexible. The potential for farmers to adapt production technologies in response to unforeseen events is at the core of the state‐contingent approach. Advanced in Chambers and Quiggin (2000), the theory contends that producers can manage uncertainty through the allocation of productive inputs to different states of nature. In this article, we test the assumption that farmers’ observed behaviour is consistent with the state‐contingent production theory using farm‐level data from Australia. More precisely, we estimate the milk production technology for a sample of irrigated dairy farms from the southern Murray–Darling Basin over the period from 2006–2007 to 2009–2010.     

Elicitation of irrigators' risk preferences from observed behaviour

Water trading in the Murray–Darling Basin of Australia has developed to the point where it is a common adaptation tool used by irrigators, making it an apt case study to elicit the marginal value of irrigation water and irrigators' risk preferences in two key industries with differing levels of water dependence. Our data come from large‐scale and representative surveys of irrigated broadacre and horticultural farms in the Murray–Darling Basin over a 6‐year period. The marginal contribution of irrigation water to profit is estimated at $547 and $61/ML on average in horticulture and broadacre, respectively. Horticultural irrigators are found to be averse to the risk of large losses (downside risk) while broadacre irrigators are averse to the variability (variance) of profit.     

Using proportional modeling to evaluate irrigator preferences for market‐based water reallocation

Irrigators’ policy preferences for water reallocation programs usually take the form of proportional data, where one option will be relatively more or less favored than another in the composition of a government's total budget apportionment to address water reform. This study applies a zero‐one inflated beta regression to model Murray–Darling Basin irrigators’ preferences for market‐based water policy programs. Market‐based arrangements are more likely to provide efficient solutions to water reallocation problems, particularly where future uncertainty and appropriate pricing induce irrigator preferences for such programs. Our modeling of drivers of irrigator preferences for government expenditure on market‐based programs identified different determinants of zero (a corner solution) and proportional outcomes for the reallocation of Murray–Darling Basin water. In addition, the proportional modeling identifies some variables (namely, state regional influences, the type of farm production and recent debt, low income, or water allocation stressors) that increase engagement with market‐based programs. Interestingly, while price variables are important and statistically significant, they appear to be less relevant to program engagement than other influences.     

Allocation trade in Australia: a qualitative understanding of irrigator motives and behaviour*

Governments in Australia are purchasing water entitlements to secure water for environmental benefit, but entitlements generate an allocation profile that does not correspond fully to environmental flow requirements. Therefore, how environmental managers will operate to deliver small and medium‐sized inundation environmental flows remains uncertain. To assist environmental managers with the supply of inundation flows at variable times, it has been suggested that allocation trade be incorporated into efforts aimed at securing water. This paper provides some qualitative and quantitative perspective on what influences southern Murray–Darling Basin irrigators to trade allocation water at specific times across and within seasons using a market transaction framework. The results suggest that while irrigators now have access to greater risk‐management options, environmental managers should consider the possible impact of institutional change before intervening in traditional market activity. The findings may help improve the design of intervention strategies to minimise possible market intervention impacts and strategic behaviour.     

Economic effects of water recovery on irrigated agriculture in the Murray‐Darling Basin*

In October 2010, the Murray‐Darling Basin Authority (MDBA) proposed that a range of 3000–4000 GL per year, on average, of additional water be made available for the environment in the Murray‐Darling Basin (MDB) to mitigate the effects of what it considers to be inadequate environmental flows. To help quantify the costs of this water reallocation, a hydro‐economic model was constructed based on the 19 regions of the MDB. The model results indicate the following: (i) substantial reductions in surface water extractions of up to 4400 GL per year impose only a moderate reduction on net profits in irrigated agriculture, Basin wide, given competitive water markets, but the effects are much more pronounced in particular regions/catchments and (ii) the costs of the water reallocation are comparable with the amount budgeted by the Australian government to acquire water from willing sellers and increase environmental flows if inter‐regional water trade is unrestricted.     

Climate Change,Uncertainty, and Adaptation: The Case of Irrigated Agriculture in the Murray–Darling Basin in Australia

Climate change is likely to have substantial effects on irrigated agriculture. Extreme climate events, such as droughts, are likely to become more common. These patterns are evident in median projections of climate change for the Murray–Darling Basin in Australia. Understanding climate change effects on returns from irrigation involves explicit representation of spatial changes in natural stocks (i.e., water supply) and their temporal variability (i.e., frequency of drought states of nature) and the active management responses to capital stocks represented by mitigation and alternative adaptation strategies by state of nature. A change in the frequency of drought will induce a change in the allocation of land and water between productive activities. In this paper, a simulation model of state-contingent production is used to analyze the effects of climate change adaptation and mitigation. In the absence of mitigation, climate change will have severe adverse effects on irrigated agriculture in the Basin. However, a combination of climate mitigation and adaptation through changes in land and water use will allow the maintenance of agricultural water use and environmental flows. Le changement climatique risque d’avoir des répercussions considérables sur l’agriculture irriguée. Les phénomènes climatiques extrêmes, tels que les sécheresses, risquent de devenir plus fréquents. Ces phénomènes sont mis en évidence dans les projections médianes du changement climatique établies pour le bassin de Murray–Darling, en Australie. Pour comprendre les répercussions du changement climatique sur le rendement des cultures irriguées, il faut disposer d’une représentation explicite des changements spatiaux qui touchent les stocks naturels (c.-à-d. l’approvisionnement en eau) et de leur variabilité temporelle (c.-à-d. les états de la nature de la fréquence de la sécheresse) et assurer une gestion active des stocks de capital grâce à des stratégies d’atténuation et d’adaptation selon l’état de la nature. Une variation de la fréquence des sécheresses entraînera une modification de l’allocation des terres et de l’eau entre les activités de production. Dans le présent article, nous avons utilisé un modèle de simulation états-contingences pour analyser les répercussions des stratégies d’atténuation du changement climatique et d’adaptation à ce changement. En l’absence de stratégies d’atténuation, le changement climatique aura des répercussions défavorables sur l’agriculture irriguée dans le Bassin. Toutefois, des stratégies d’atténuation combinées à des stratégies d’adaptation comprenant des changements dans l’utilisation des terres et de l’eau permettront de maintenir l’utilisation de l’eau à des fins agricoles et les débits environnementaux.     

Achieving environmental flows where buyback is constrained

Theory suggests that the development of common property increases national welfare, and consistent with this thinking Australia's Murray–Darling Basin (MDB) Plan uses a common property approach to recover environmental water rights in the national interest. Two water recovery instruments are used: purchasing water rights (buyback) from farmers, and saving water by subsidising irrigator adoption of technically efficient technology. A moratorium on buyback has focused environmental recovery on subsidised technically efficient technology adoption. Economists argue that national welfare is maximised via buyback and highlight the limitations of efficiency savings to recover sufficient environmental water. A risk is that water recovery targets may be reduced in future, limiting welfare gains from water reform. This article evaluates possible welfare trade‐offs surrounding environmental water recovery outcomes where arbitrary limits on buyback are imposed. Results suggest that, on average, strategies which attempt to obtain >1500 gigalitres (GL) of water from on‐farm efficiency investments will only provide sufficient resources to meet environmental objectives in very wet states of nature. We conclude that reliance on technically efficient irrigation infrastructure is less economically efficient relative to water buyback. Importantly, the transformation of MDB irrigation will significantly constrain irrigators' future capacity to adapt to climate change.     

Water use and salinity in the Murray–Darling Basin: A state-contingent model*

The supply of water for irrigation is subject to climatic and policy uncertainty. The object of the present paper is to show how the linear and non-linear programming models commonly used in modelling problems such as those arising in the Murray–Darling Basin may be adapted to incorporate a state-contingent representation of uncertainty. Estimates showing the potential value of improved water use are also derived.     

Presumptions of linearity and faith in the power of centralised decision‐making: two challenges to the efficient management of environmental water in Australia

Water policy in the Murray‐Darling Basin continues to be dominated by the trade‐offs between agricultural and environmental interests. This has recently been played out with the acrimonious debate that circumscribed the release of the Guide to the Murray‐Darling Basin Plan. In this paper, we argue that too much emphasis has been placed on the volume of held water as an indicator of environmental benefit. We also contend that there is an attendant presumption of linearity in the relationship between volumes of held water and environmental benefit which could lead to perverse outcomes. A second problem is that there is too much enthusiasm for contemplating the solutions to water management problems as residing primarily at the federal level of government. These factors stand to ultimately limit the efficient delivery of environmental objectives.     

Risk management strategies using seasonal climate forecasting in irrigated cotton production: a tale of stochastic dominance

Decision-making in agriculture is carried out in an uncertain environment with farmers often seeking information to reduce risk. As a result of the extreme variability of rainfall and stream-flows in north-eastern Australia, water supplies for irrigated agriculture are a limiting factor and a source of risk. The present study examined the use of seasonal climate forecasting (SCF) when calculating planting areas for irrigated cotton in the northern Murray Darling Basin. Results show that minimising risk by adjusting plant areas in response to SCF can lead to significant gains in gross margin returns. However, how farmers respond to SCF is dependent on several other factors including irrigators' attitude towards risk.     

Impacts of climate change on lower Murray irrigation*

This article evaluates irrigated agriculture sector response and resultant economic impacts of climate change for a part of the Murray Darling Basin in Australia. A water balance model is used to predict reduced basin inflows for mild, moderate and severe climate change scenarios involving 1, 2 and 4°C warming, and predict 13, 38 and 63% reduced inflows. Impact on irrigated agricultural production and profitability are estimated with a mathematical programming model using a two‐stage approach that simultaneously estimates short and long‐run adjustments. The model accounts for a range of adaptive responses including: deficit irrigation, temporarily following of some areas, permanently reducing the irrigated area and changing the mix of crops. The results suggest that relatively low cost adaptation strategies are available for a moderate reduction in water availability and thus costs of such a reduction are likely to be relatively small. In more severe climate change scenarios greater costs are estimated. Adaptations predicted include a reduction in total area irrigated and investments in efficient irrigation. A shift away from perennial to annual crops is also predicted as the latter can be managed more profitably when water allocations in some years are very low.     

Effective use of public funding in the Murray‐Darling Basin: a comparison of buybacks and infrastructure upgrades

Policy instruments designed to increase environmental flows in the Murray–Darling Basin are compared using TERM‐H₂O, a detailed, dynamic regional CGE model. Voluntary and fully compensated buybacks are much less costly than infrastructure upgrades as a means of obtaining a target volume of environmental water, even during drought, when highly secure water created by infrastructure upgrades is more valuable. As an instrument of regional economic management, infrastructure upgrades are inferior to public spending on health, education and other services in the Basin. For each job created from upgrades, the money spent on services could create between three and four jobs in the Basin.     

The impact of drought and water scarcity on irrigator farm exit intentions in the Murray–Darling Basin

Drought and future water scarcity in the Murray–Darling Basin (MDB) will continue to restructure the irrigation industry in the coming decades. There has been little work conducted in Australia that has modelled farm exit or exit intention. ABARES farm survey data were used to model irrigators’ farm exit intentions across the southern MDB from 2006 to 2013. In particular, we examined the hypotheses that drought and water scarcity positively impacted on farm exit intentions and that it is the poorest performing farms that intend to exit in times of drought. Results revealed that water scarcity impacts varied considerably. There was only weak evidence to suggest that irrigators’ exit intentions were higher in times of drought, but there was stronger evidence to support the influence of a lagged water scarcity impact on farm exit intentions during periods of nondrought (e.g. intending to exit at times when the property market was less depressed). There was also strong evidence that poorer performing farms (measured by rates of return and higher debt over a certain level) were more likely to have exit intentions in drought periods, but not necessarily so in nondrought periods. Older age is the most consistent predictor of farm exit intentions across all industries, though it was most significant in drought periods.     

Policy review of water reform in the Murray–Darling Basin,Australia: the “do's” and “do'nots”

The water reforms undertaken in the Murray–Darling Basin, Australia since 2007 have been viewed as a model for other countries seeking to respond to water insecurity. Here, a policy review is provided of this water reform and whether it delivers on key environmental objectives in the 2007 Water Act (the Act). The evaluation includes a review of the 2012 Basin Plan, a key instrument of the Act, and complementary policies associated with the acquisition of water entitlements for the environment via direct (reverse tenders) and indirect (infrastructure subsidies) means. Using the objects of the Act as a benchmark, an evaluation is provided of the following: (i) planned reductions in irrigation water extractions in the 2012 Basin Plan; (ii) risks associated with the 2018 amendments to the Basin Plan that, collectively, allow for an increase in irrigation water extractions of some 22 per cent, relative to the sustainable diversion limits specified in the 2012 Basin Plan; (iii) Basin‐scale environmental outcomes achieved, as of the end of 2018; and (iv) economic effects of direct and indirect methods of acquiring water for the environment. Findings from the review generate the “Do's” and “Do Nots” of water reform for Australia, and possibly other countries, when managing the trade‐offs between water for irrigation and the environment.     

Repurchase of renewal rights: a policy option for the National Water Initiative*

Management of the Murray–Darling river system involves a large number of users with imprecisely defined rights, and an aggregate rate of resource use that is environmentally unsustainable. One possible policy response is to make formal or informal contracts with users, under which users receive current benefits in return for a commitment to forgo usage rights in future. In this paper, this issue is explored with specific reference to the possibility of repurchasing the renewal rights for irrigation licenses.     

Is there evidence of insider trading in Australian water markets?

Insider trading is a much studied form of market manipulation in the financial market literature. However, studies addressing the issue of insider trading in resource markets, and in particular water markets, are rare. This study investigates the occurrence of insider trading practices around important water market allocation announcements in the Goulburn temporary water market trading zone in the Murray–Darling Basin, Australia, which is one of the largest and longest operating water market districts in the world. Nine years of daily water allocation volume and price transactions between 2008 and 2017 are modelled, with some evidence found of abnormal price movements in the 3 or 5 days preceding water allocation announcements, and especially before the introduction of insider trading rules in 2014. However, although the results do suggest some very weak statistically significant evidence that insider trading may still be present in Goulburn water markets post‐2014, it is just as feasible that our results may also reflect an increased sophistication of trader behaviour over time.     

Double trouble: the importance of accounting for and defining water entitlements consistent with hydrological realities*

When entitlements to access water in fully allocated river and aquifers are specified in a manner that is inconsistent with the ways that water arrives, flows across and flows through land, inefficient investment and water use is the result. Using Australia's Murray Darling Basin as an example, this paper attempts to reveal the adverse economic and water management consequences of entitlement and water sharing regime misspecification in regimes that allow water trading. Markets trade water products as specified. When entitlements and the water sharing system are not designed in a way that has hydrological integrity, the market trades the water management regime into trouble. Options for specification of entitlement and allocation regimes in ways that have hydrological integrity are presented. It is reasoned, that if entitlement and allocation regime are set up in ways that have hydrological integrity, the result should be a regime that can autonomously adjust to climatic shifts, changes in prices and changes in technology without compromising environmental objectives.     

Environmental economics and the Murray–Darling river system

Much concern about the negative environmental consequences of agricultural development in Australia, including salinisation, waterlogging and algal blooms, has focused on the problems of the Murray–Darling Basin. The aim of this article is to provide an overview of the environmental problems of the Murray–Darling Basin from an economic perspective, and a selective survey of the relevant economic literature, including theoretical analysis, modelling and contributions to the development of water policy. In attempting to understand the complex problems of the Murray–Darling Basin, an eclectic approach drawing on externality, sustainability and property rights perspectives seems most appropriate.     

Evidence of climate change impacts on crop comparative advantage and land use

Relative agricultural productivity shocks emerging from climate change will alter regional cropland use. Land allocations are sensitive to crop profits that in turn depend on yield effects induced by changes in climate and technology. We develop and apply an integrated framework to assess the impact of climate change on agricultural productivity and land use for the U.S. Northern Great Plains. Crop-specific yield–weather models reveal crop comparative advantage due to differential yield impacts of weather across the region's major crops, that is, alfalfa, wheat, soybeans, and maize. We define crop profits as a function of the weather-driven yields, which are then used to model land use allocation decisions. This ultimately allows us to simulate the impact of climate change under the RCP4.5 emissions scenario on land allocated to the region's major crops as well as to grass/pasture. Upon removing the trends effects in yields, climate change is projected to lower yields by 33–64% over 2031–2055 relative to 1981–2005, with soybean being the least and alfalfa the most affected crops. Yield projections applied to the land use model at present-day input costs and output prices reveals that Dakotas’ grass acreage will increase by up to 23%, displacing croplands. Wheat acreage is expected to increase by up to 54% in select southeastern counties of North Dakota and South Dakota, where maize/soy acreage had increased by up to 58% during 1995–2016.     

Modelling drought and recovery in the southern Murray‐Darling basin*

The prolonged drought from 2006–07 to 2008–09 in south‐eastern Australia presented severe difficulties for dry‐land and irrigation farmers in the southern Murray‐Darling basin. A dynamic multi‐regional computable general equilibrium model (TERM‐H2O) is used to estimate the economy‐wide small region impacts during and after drought. Drought reduces real GDP in some small regions by up to 20 per cent. Irrigation water trading and farm factor movements alleviate losses. The drought results in an estimated 6000 jobs being lost across the southern basin. Depressed farm investment during drought results in farm capital not returning to baseline levels after drought. Consequently, job numbers in 2017–18 remain 1500 below forecast in the southern basin.